Ratio between length of right index and ring fingers can predict facial attractiveness .A look at the fingers of a man can give information about if women are attracted to his face.
If you want to know how attractive a guy is, look down … at his hands, that is. The ratio between the length of his right index and ring fingers is linked to facial attractiveness, a new study finds.
The ratio, called the 2D:4D because it compares the length of the second digit with the fourth digit, makes sense since that ratio is driven by the sex hormone testosterone, the researchers say
“What we found was that 2D:4D ratio can predict face attractiveness. The more masculine the 2D:4D is, the more attractive is the face,” said study researcher Camille Ferdenzi at the University of Geneva in Switzerland. “The amount of sex hormones you are exposed to before birth contributes to how your face develops and how attractive it becomes.” (Past research has shown that gals love caveman-like masculine faces.)
Oddly enough, this is because of the amount of testosterone that a fetus is exposed to in the end of the first trimester, when the testes start to develop. The more testosterone, the higher this 2D:4D ratio is, and also, the higher-quality sperm the male produces. This is different from other sexual and masculine traits, such as voice frequency and body odor, which are regulated by levels of adult testosterone.
“There are lots of things that are regulated by testosterone during puberty and in adults,” John Manning, a researcher from Swansea University in Wales who wasn’t involved in the study, told LiveScience. “The point of this paper is to see if the early fetal spike affects things like attractiveness.”
The more testosterone, the longer a fetus’ right ring finger grows (yes, just this one finger). The index finger is more sensitive to fetal estrogen levels. If these two fingers are the same length (measured from the bottom crease), the 2D:4D ratio is 1; if the ring finger is longer, the ratio is lower than 1. So the longer the ring finger is than the index, the more fetal testosterone you’d expect — and, eventually, a hotter guy facially.
While the experiments required to definitively prove this correlation (sampling in utero testosterone during pregnancy, or treating some fetuses with testosterone and measuring finger length) would be unethical, many researchers believe in the connection. Tests in rats show that increased testosterone causes higher 2D:4D ratios, and some human hormonal diseases show differences in this ratio.